In recent years, VOCs have drawn attention as substances that cause allergy symptoms or sick building syndrome, which develops into health hazards such as headaches and dizziness. The VOCs are known to be emitted from electronic apparatuses such as personal computers, copiers, and printers. Furthermore, among these electronic apparatuses, image forming apparatuses such as copiers and printers not only emit VOCs, but also have a problem with peculiar odors that are generated from heated sheets of paper or heated toner.
In order to deal with such a problem of generation of volatile chemical substances such as VOCs and odors from image forming apparatus, image forming apparatuses such as copiers and printers are provided with VOC honeycomb filters (which use activated carbon or catalysts) or negative ion generating devices for catching volatile chemical substances such as VOCs and odors.
For example, Japanese Patent Application Publication, Tokukai, No. 2007-47496 A (Publication Date: Feb. 22, 2007) proposes a technique for emitting negative ions by applying a high negative voltage to a needle electrode located downstream of fixing means in the direction that a sheet is conveyed in an image forming apparatus, and for reducing a positively charged odorous component that is generated when a fixing section is heated.
However, the conventional technique has the following problems.
First, in the case of use of a filter to catch volatile chemical substances such as VOCs and odors, there naturally occurs aged deterioration in performance. In order to overcome such aged deterioration in performance, the honeycomb structure is made finer to increase in area of contact with air currents. However, there is a trade-off, i.e., a hindrance to passage of heat out of the image forming apparatus, which causes a rise in temperature in the image forming apparatus, and such a rise in temperature consequently brings about a secondary negative effect.
Second, in the case of use of a needle electrode as a negative ion generating device, foreign matter (e.g., Si-based material) adheres to the needlepoint to cause discharging deficiency, thus causing a decrease in emissions of negative ions. Further, since the needlepoint is blunted over time by application of a high voltage, deterioration in performance cannot be avoided.